Hi Sr,
If your master data loads had generated SID s properly you won't receive above error.
Above error is related SIDs for master data. which you selected referential integreity for one of the attribute. While loading its check for sids. if no sids, it may throw an error.
http://help.sap.com/saphelp_tm80/helpdata/en/48/21d2f39a224e70e10000000a42189c/content.htm
As stated by Srikanth voodi, try to run ACR and retrigger the DSO DTP. Before trigger make request red at dso and delete the old one.
Thanks